CVE-2024-49889: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid use-after-free in ext4_ext_show_leaf() In ext4_find_extent(), path may be freed by error or be reallocated, so using a previously saved *ppath may have been freed and thus may trigger use-after-free, as follows: ext4_split_extent path = *ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode, path) eh = path[depth].p_hdr // path use-after-free !!! Similar to ext4_split_extent_at(), we use *ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way. Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 5.10.227
linux	linux_kernel	5.11 — 5.15.168
linux	linux_kernel	5.16 — 6.1.113
linux	linux_kernel	6.2 — 6.6.55
linux	linux_kernel	6.7 — 6.10.14
linux	linux_kernel	6.11 — 6.11.3

References

Advisories & Patches

https://git.kernel.org/stable/c/2eba3b0cc5b8de624918d21f32b5b8db59a90b39 https://git.kernel.org/stable/c/34b2096380ba475771971a778a478661a791aa15 https://git.kernel.org/stable/c/4999fed877bb64e3e7f9ab9996de2ca983c41928 https://git.kernel.org/stable/c/4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 https://git.kernel.org/stable/c/8b114f2cc7dd5d36729d040b68432fbd0f0a8868 https://git.kernel.org/stable/c/b0cb4561fc4284d04e69c8a66c8504928ab2484e https://git.kernel.org/stable/c/d483c7cc1796bd6a80e7b3a8fd494996260f6b67

Other References

https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html https://cert-portal.siemens.com/productcert/html/ssa-265688.html https://cert-portal.siemens.com/productcert/html/ssa-355557.html

Frequently Asked Questions

What is CVE-2024-49889? +

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid use-after-free in ext4_ext_show_leaf() In ext4_find_extent(), path may be freed by error or be reallocated, so using a previously saved *ppath may have been freed and thus may trigger use-after-free, as follows: ext4_split_extent path = *ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode, path) eh = path[depth].p_hdr // path use-after-free !!! Similar to ext4_split_extent_at(), we use *ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way. Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2024-49889? +

CVE-2024-49889 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-49889? +

CVE-2024-49889 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-49889? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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